


Favor

by CharWright5



Category: Haikyuu!!
Genre: Alpha/Beta/Omega Dynamics, Alternate Universe, Alternate Universe - College/University, Childhood Friends, Confessions, Fluff, M/M, Reunions, background AtsuHina
Language: English
Status: Completed
Published: 2020-10-11
Updated: 2020-10-11
Packaged: 2021-03-08 05:00:02
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,775
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26950099
Author URL: https://archiveofourown.org/users/CharWright5/pseuds/CharWright5
Summary: Atsumu begs Osamu for a favor, but by the end of the night, Osamu wonders if maybe he's the one who owes his brother.
Relationships: Kageyama Tobio/Miya Osamu
Comments: 7
Kudos: 317





	Favor

**Author's Note:**

  * For [Hachimomo](https://archiveofourown.org/users/Hachimomo/gifts).



> Happy happy birthday to the wonderful Pandora! Thank you so much for all your love and support. I hope you enjoy! 🍙💙

Growing up, privacy wasn't a thing that existed thanks to a shared bedroom. At any given moment, one of them could barge in, interrupting whatever the other had been up to, no matter how personal or intimate. Pretty damn awkward when they were teenagers and knots popped simply from dreams and they had to waddle to the bathroom to find relief behind the only locked door of the apartment.

Now that they were in their twenties, at university, and in a two bedroom apartment, Osamu relished having his own space and all the privacy he could want.

Most of the time anyway.

Because Atsumu was still an asshole who would barge in without knocking, even when Osamu put his " _Do Not Disturb_ " sign on the door so he could study in peace.

He was gonna have to invest in a locking doorknob. Maybe one of those security bars or chains that Atsumu couldn't pick or unlatch. It would be worth losing the security deposit if it meant his brother couldn't come in without knocking or being permitted to.

Osamu heaved a sigh, head hanging as he sat at his desk. He'd actually managed to make good headway, too, thanks to Atsumu being in class, but now all that was ruined because the shithead apparently needed attention.

"Samuuuu!" he extended the name in excitement and Osamu grimaced without turning around to look at him. No good ever came from that tone of voice. "What're ya doing this evening?"

Osamu lifted his textbook over his head, passages highlighted and notes scribbled in the margins. "Yer lookin' at it."

An ugly snort before Atsumu made his way over and snatched said textbook away. "Boh-ring!" Atsumu sing-songed, tossing the book onto the desk with a thump.

As it closed.

And Osamu lost his page.

"Dick," he muttered absently, the insult second-natured at this point. He reopened his book to try and find his page only for Atsumu to flip it closed again. "Oi!"

Atsumu sat on the edge of the desk, smirking down at him, and Osamu felt his stomach sink. No good ever came from that look either. "We're going out tonight."

"No. We're not."

"Yes. We are." Atsumu kept smirking like he'd won and Osamu glared. "Yer grades are fine. You can put aside your nerdiness for a night and have some fun."

Osamu's eyes narrowed in suspicion this time as he crossed his arms and leaned back in his chair. Atsumu never offered to take Osamu out for fun. The nerdy comment and telling Osamu to go enjoy himself was frequent, yes, but never had he been so adamant about Osamu doing it.

"What're you up to?"

Atsumu actually had the gall to look offended, a hurt noise coming from him… before he dropped the act, knowing Osamu didn't buy any of his bullshit. Never had, never will. "Fine. I need a favor."

Shit.

Osamu grimaced, turning away. These never ended well. He always ended up doing some shit he didn’t want to and he wound up resenting Atsumu so much they didn’t speak for a week.

But given the determined set to Atsumu’s jaw and the desperate look in his eye, Osamu knew he was gonna wheedle and cajole and beg and annoy until he gave in and did the damn favor anyway. He was stuck in a lose-lose.

Well, maybe. There was a chance that if he did this favor and it went south, then Atsumu would fuck off and leave him alone for a while and he could finally get some damn peace.

“You’ll owe me,” he stated in a harsh tone that gave no room for an argument.

But Atsumu just nodded vehemently, excitedly, further raising Osamu’s suspicions. “Anything ya want.”

Oh, this was definitely not good. Osamu was gonna regret the hell out of this.

HIs eyes narrowed in suspicion. “The fuck’re you up to?”

Atsumu went wide eyed, hands up in innocence. “Nothing! Just.” He wrung the back of his neck. “Ya know that Omega in my lit class? The cute little redhead?”

“The one you’ve been failing at flirting with and mooning over all semester?” Yeah, Osamu was unfortunately very familiar with Hinata Shoyo and all the details about not just the man himself, but Atsumu’s clownery in an attempt to get his attention--and phone number. He was beyond sick of hearing his dumbass brother wax poetic about his freckles or the way he crinkled his eyes when he smiled real big. It was sickening.

“Yeah, that one.”

Case in point: Atsumu was so whipped for the guy that he didn’t bother trying to argue or defend himself.

“Anyway, finally scored a date with him tonight!”

Osamu cocked an eyebrow, mind whirling as he tried to figure out what the hell that had to do with him and his plans for the evening.

Unless…

“Don’t tell me yer pulling some knothead asshole bullshit where ya had a date with some other Omega and need me to go out with him so ya can date Hinata?”

“Fuck no!” Atsumu objected in way too loud a voice, offended once more at his brother’s statement. “Shoyo is the only one for me. Pretty sure he’s my Fated Pair.”

Aaaand there he went again with that Fated Pair shit. It was all Osamu had heard since Atsumu had first laid eyes on the Omega the first day of the new school year. He was gonna vomit.

It wasn’t that he didn’t believe in such a thing, just that he knew how rare it was and how easily it was for people to _think_ they’d found their Fated Pair but actually hadn’t. But Atsumu was a swooning, mooning romantic, especially out of the two of them, and had been convinced of it from the get-go.

Whatever. Maybe now that he had Hinata, he’d be out the apartment more often and Osamu can enjoy some much needed quiet time.

“Problem is,” Atsumu went on, face falling into a pout, and Osamu knew this was the favor. “Shoyo’s parents are old fashioned and don’t want him going out with an Alpha by himself.”

Osamu scoffed and rolled his eyes at the archaic thoughts. Yeah, there were still Alphas who took advantage of weaker Omegas, still those who harassed and assaulted and blamed it on Omega scents and pheromones. But for the most part, Alphas were refined, dignified, cordial, respectful. To prevent their kid from going out with one by himself was overprotective and unnecessary.

“Why’s he need a chaperone? He’s an adult and in college.”

“He still lives with his parents,” Atsumu explained, flipping a hand dismissively. “Whatever. Anyway, point is I need someone to double with me.”

The eyebrow went up again. Obviously Atsumu wasn’t asking Osamu to be a chaperone. No way would Hinata’s parents agree to the guy going out with _two_ Alphas. Meaning Atsumu was asking Osamu to come out on some sort of blind double date in a “safety in numbers” thing to reassure the Hinata parents.

Which…

Shit.

Osamu looked at his textbook forlorn. He knew that if Atsumu didn’t get his date with Hinata, he was personally never gonna know peace again. His only hope at a good life was to go along with this, even if the thought of a blind date gave him hives. He and his brother’s taste in partners were vastly different and Osamu could only shudder at the thought of who Atsumu would attempt to set him up with.

God, Atsumu was gonna owe him bigger than Osamu previously thought.

“Yer paying for all the food.”

Atsumu scoffed. “I ain’t got that kinda money. I’ll be in debt for the next five years.”

Osamu shoved him, rocking him off the desk where he unfortunately caught himself with his foot before he fell. “You’ll owe me big and ya can’t argue when I call ya on it.”

“Fine.”

Damn. Atsumu was more desperate than Osamu thought. He was gonna have to think of something _really_ big and _really_ good.

With a sigh, Osamu waved a hand in acquiescence. “Fine. I’ll go.”

Atsumu punched the air and let out a victory cry before slamming into Osamu for a hug. “Thanks, man!”

“Yeah, yeah. Get off me, ya fuck.”

A few slaps to the back then Atsumu was straightening up and heading to the door. “Oh! We’re going to the festival so ya gotta put your _yukata_ on. We’re leaving in a half an hour.”

The door closed on the textbook Osamu hurled at his brother.

~*~*~*~*~*~

Unfortunately for Osamu, the only _yukata_ he had was one that matched his brother’s. Their mother had been very into the matchy-matchy twin thing, something that they both wound up resenting, dyeing their hair different colors in high school to differentiate themselves and so people would stop calling them the wrong names. The only difference in their outfits were the socks Osamu wore with his _geta_ sandals, his feet easily getting cold and not wanting them to get covered in who knew what as he walked the festival area.

Naturally, the festival was crowded, most of the patrons dressed in a similar fashion, while others opted for more modern clothing. Osamu found himself pissed that he was stuck in something so boring, deciding his brother owed him double now, as the two of them tried to make their way through the throng of people to a predetermined meeting spot.

“Shoyo says they’re here and waiting,” Atsumu stated, sounding oddly nervous, as he put his cell phone back in his pocket. Osamu figured it made sense given the situation, that he was finally going out with the Omega he’d been chasing for months.

Still, he hadn’t signed up to deal with a nervous wreck all evening. Atsumu needed to get his shit together.

“Atsumu-san!” a semi-familiar voice called out and Osamu turned to find a short redhead standing on a bench, waving his arms wildly as he grinned, sleeves of his _yukata_ flapping about. Even over the din of all the conversations and yells and music, Osamu picked up his brother inhaling sharply at the sight before breathing out a swear.

“I may not survive the night.”

Osamu snorted. “You better. Ya owe me and I’m gonna collect.”

“Yeah, yeah,” Atsumu replied absently, more distracted by the sight he was staring at, waving back as the two of them drew closer to the waiting Omega who was now bouncing on the balls on his feet… still on the bench.

Although his friend had turned around and was calling him a dumbass and yelling to be careful.

Ah. Must’ve been Osamu’s date.

Shit. Time to get it over with, he figured.

Hinata batted his friend away as the twins reached them, his attention focused on Atsumu, eyes sparkling. Just from observing them, Osamu knew that his brother had nothing to worry about and that honestly, he should’ve asked the guy out ages ago. It was obvious that Hinata liked him just as much back, scent so strongly full of excitement and joy that it was easily smelled even above all the other aromas of food and people.

“Hi, Atsumu-san,” he breathed softly.

“Shoyo-kun,” Atsumu said just as gently, a side of his brother Osamu had never really seen before, and he turned away to give them their privacy as Atsumu helped Shoyo down.

“Boke,” his friend grumbled, arms folded over his own blue striped _yukata_.

Osamu wondered if he should introduce himself, if the guy even realized he was there. Surely, Hinata had told him, right? He wished he could smell the guy, figure out what was going on with him, but all he caught was the fried food and a mix of countless people that made it hard to differentiate.

“Uh, hi?” he tried, the guy jerking slightly, tensing up before he began turning towards him. “I’m Osa--”

He stopped breathing.

He’d recognize those eyes anywhere.

Big and blue, joined by the same button nose he remembered from childhood. Gone was the baby fat from his cheeks, his jaw and cheekbones now sharper and more defined, lips poutier and fuller. And his hair was the same shade of midnight black, in the same style as it had always been.

“Tobio?” he breathed out shakily, his heart pounding in his chest and his stomach flipping and his skin buzzing and holy _shit_!

Those blue eyes narrowed then went wide with recognition as it dawned on him, too. “‘Samu?”

A smile spread across his face and before he knew it, Osamu had the guy wrapped up in a tight hug, eyes clenched tight to hold back the tears threatening to fall. He hadn’t seen Tobio in over a decade, since his childhood best friend moved to Sendai to live with his grandfather after his parents passed. And man, he fit in Osamu’s arms in the same way, even though they both had grown taller, broader, more muscular. And his scent was the exact same, blueberries and sugar, sweet and buzzing in Osamu’s head like when they were kids, playing together at the park, running around and chasing one another until they fell into a heap on the ground.

Only now… now the buzzing was intensified, prickling different parts of his brain and… yeah, going straight into his underwear.

He should move away.

Except Tobio was hugging him back, clutching onto his _yukata_ , nose buried against Osamu’s scent gland at the side of his neck and inhaling deeply. Osamu felt a vibration against his chest before he picked up the sound of Omega purring and he let out a rumble of his own in response.

It was _Tobio_. His Tobio.

“Should we leave you two alone or what?”

And that was Atsumu, who may have signed his death warrant with that, given how Tobio’s purring cut off and he was pulling away. 

Fuck. Fuck, shit, fuck.

Osamu turned to glare at his brother, lip curled. Atsumu grinned, smug.

Right. Osamu was gonna throttle him.

“‘Scuse us a second,” he rushed out as he grabbed his brother’s arm and hauled him away, not stopping until they were across the walkway. And only when they stopped and he’d released him did Osamu punch Atsumu in the shoulder, making him cry out.

“What the fuck?”

“What the fuck yerself!” Osamu yelled. “Why didn’tja tell me it was _Tobio_ who’d be my date?”

Atsumu glanced over Osamu’s shoulder, presumably at the aforementioned Omega, then turned back to his brother. “Didn’t think it mattered.”

Osamu punched him in the same exact spot.

“Ah! Quit it out, asshole!”

Osamu did it a third time and Atsumu hit him back.

“Dude! I didn’t know, okay? Shoyo just said he’d invite his friend ‘Kageyama’. I didn’t remember Tobio’s last name. He was more your friend than mine, remember?”

Osamu glared. Of fucking course he remembered. He’d been incredibly possessive of Tobio when they were kids, Alpha instincts already rearing their ugly head even before he’d hit puberty and fully presented. He'd wanted to keep that particular person to himself, given the fact that he'd had to share everything else with his twin. But Tobio was his and his only.

The crush he’d had on the guy had only exacerbated that need to keep Tobio away from his brother.

And he was feeling it again, despite the logical part of him knowing that Atsumu was only interested in Hinata and that… well, Osamu really had no claim to Tobio. He’d been around him for a minute--if that--over the past decade.

Damn Alpha instincts. Now he knew why Hinata’s parents didn’t want him going out with an Alpha by himself.

“So I take it yer okay with this li’l twist of fate?” Atsumu said with a smirk that was way too smug for his own good.

Osamu punched him in that same spot a fourth time, hoping like hell it bruised, before quickly moving out of range and heading back to the two waiting Omegas.

“Everything okay?” Shoyo asked, almost nervous, eyes focused on where Atsumu was rubbing the join of his shoulder where Osamu had repeatedly nailed him.

“Fine,” Atsumu practically swooned, dropping his hands to place them on Shoyo’s hips, head bent down to give the shorter man a disgusting soft smile.

Osamu turned away.

To find Tobio already watching him, teeth sinking into his bottom lip as a nervous glint took over his eye.

“Sorry,” Osamu apologized, feeling sheepish, heart thudding slowly. “I just. Didn’t expect to see ya again.”

Tobio shrugged and his face morphed into a sad smile. “Me too. I was kinda hoping when Shoyo said ‘Miya’, but it could’ve been any Miya so.” He trailed off, shrugged again, then his own gentle smile spread across his face. “I’m glad it was you though.”

Osamu felt like he was in some romance manga, when the lead character gets shot in the heart with an arrow and there’s some sorta “thud” or “thunk” sound effect floating above them. He wondered if it was visible.

Maybe evident in his scent, he realized, as his nose grew more attuned and managed to pick up Tobio’s, pick up on the happiness and excitement making it sweeter.

“I’m glad it was you, too,” Osamu replied, feeling soft and warm and fuzzy.

Until Tobio’s stomach growled.

And oh hell no, he wasn’t about to let anyone go hungry, especially not this Omega in particular.

“D’ya wanna go grab some food to start?”

Tobio sagged in relief. “Fuck yes, please.”

Osamu let out a soft laugh and turned to their companions… only to realize Osamu and Hinata were no longer there. “We’ve been ditched.”

“They probably headed to the games.” Tobio shrugged. “I don’t mind being alone with you.”

Shit, Osamu wasn’t gonna survive the night.

His heart thundered in his chest and his fingers tingled where Tobio reached out to touch them with his own. Osamu took the initiative to lace them together, comparing how long and slender Tobio’s fingers had become over the years, how different they felt clasped together like this from when they were kids with chubbier rounder hands. Walking together with intertwined fingers reminded him of when they were kids and used to head everywhere like this, would sit in front of the tv together with their hands clasped, and their parents would coo and refer to them as “little boyfriends”.

Maybe fate would continue to be on Osamu’s side and they’d turn into more grown up boyfriends.

Peeking at Tobio out the corner of his eyes, at those beautiful blue eyes shining in the lantern light, Osamu found himself wondering if maybe Atsumu had a point about the whole Fated Pair thing… and if maybe Tobio was his…

The thoughts were pushed aside as they reached the food stalls and made a plan of attack. Osamu found himself falling for the Omega even more as he described everything he wanted and his voracious appetite and how much he loved eating. They shared plates of things together, chatting about old memories from childhood and what they’d been up to since.

Time passed as they wandered about. They played games where Osamu won Tobio a stuffed cat he clutched close to himself as they walked. Osamu got a crow mask and Tobio a fox one from a booth that sold them, picking one out for each other. They watched fire dancers and _taiko_ drummers and even a peek at a kid’s puppet show. At one point they ran into Atsumu and Hinata, who was carrying a bag of goldfish Atsumu had won for him. Osamu thought his prize was better. It wouldn’t die in a week.

The night wore on and soon Osamu and Tobio were finding a bench to sit at away from the crowd, resting tired feet. Osamu slipped his sandals off to stretch his toes, making Tobio snicker as he looked at them.

“Your feet still get cold, huh?” he commented.

Osamu smiled despite himself, touched that Tobio remembered. “Yep.”

“I remember one time, I spent the night at your house when my parents went outta town and I got scared of the storm so I crawled into your bunk and you kept putting your icy toes against my legs.”

Another grin, this one bigger as Osamu rested his feet on top of his sandals without putting the strap between his toes. “I remember that,” he replied before being hit by a bout of shyness at the memory of that night, of what else happened. “And I remember I kissed ya.” His eyes were locked onto his lap but he couldn’t help peeking at Tobio out the corner of his eye.

Tobio, who was now blushing, highlighting those sharp cheekbones once more. “My first kiss.”

“Mine, too.”

“And maybe,” Tobio began, voice small and nervous, as his hand slid over to cover Osamu’s where he was gripping the edge of the bench. “Not our last?”

Osamu’s head lifted to find Tobio watching him, biting his lower lip once more. He reached out to cup his cheek, to carefully pull his lip free with his thumb, leaning closer… “Hopefully not.”

Tobio’s head tilted as he leaned in, too, inky lashes fluttering as his big blue eyes dropped to Osamu’s lips. “I hope not, too.”

The distance was closed but Osamu had no idea by whom. He just knew that Tobio’s lips were against his, moving with his, soft and plump and oh so good. Sparks buzzed all over his skin, behind his eyes, his heart thundering away and his stomach flipping wildly. And with every inhale, he breathed in Tobio’s bright blueberry and sugar scent, sweet and strong and full of joy more than ever before.

They slowly pulled away, Osamu opening his eyes to find Tobio already smiling at him.

“Do you believe in fate?”

Tobio nudged his nose against Osamu’s. “I’m starting to.”

A laugh gusted out Osamu’s nose. “Same here.” His thumb rubbed against Tobio’s cheek, soft and warm, a lot like the look in Tobio’s eyes.

“Fireworks are starting soon.”

“Think I already saw ‘em,” Osamu replied cheesily, ignoring the part of him that cringed, that pointed out he was sounding a little _too_ much like his brother. Instead, he leaned back in to kiss Tobio some more, as the sounds of whizzing and popping fireworks exploded in the distance, weak compared to the ones his Omega was causing to dance in his vision.

And as the two of them melted together on that bench, Osamu wondered if maybe he was the one who now owed Atsumu instead of the other way around.


End file.
